My name is***** and I am sorry to hear that your dog has recurring skin issues. Your regular vet is on the right track in thinking that he likely has environmental allergies but I would be thinking they are more likely related to things like pollen, dust, mold, etc. These are common in dogs and can be very frustrating.
When I see a dog with chronic skin issues, I usually think of the following things:
1) Environmental allergies. Treatments can include prednisone or antihistamines, but can also involve the following- frequent (3x weekly bathing to physically wash off the allergens), fish oil supplements, antioxidant supplements and topical cortisone sprays on the affected areas. You can use prednisone long term if you use a low enough dose, I would aim for about 0.5mg/pound of dog maximum per day. You can also consider allergy testing and allergy shots. These treatments are available through your regular veterinarian or you can consider taking him to a dermatologist.
2) Food allergies. These are also common. I would recommend a food trial with a hydrolyzed protein diet (Science Diet, Royal Canin and Purina all have varieties of these formulas.) These diets also have a variety of other ingredients that can also help the skin and reduce the severity of environmental allergies.
3) Fleas- it is unusual to see flea allergies manifest as paw itchiness, but anything can happen. I would be sure that you have good flea control on board such as Nexguard or Comfortis.
Best regards, ***** ***** this answer helps you.
Kansas State University,
College of Veterinary Medicine Class of 2001